JP6050647B2 - Binder for firing - Google Patents

Description

  The present invention relates to a binder for firing that is removed by thermal decomposition at a low temperature.

  Among the polymer materials having the property of decomposing by heating, thermoplastic resins such as polystyrene resin, polyethylene resin, and acrylic resin are used for ceramic molding, electrode formation, It is used as a heat-decomposable binder and heat-decomposable adhesive for metal welding temporary bonding and laser-sensitive coatings.

  In general, polymer materials have a high thermal decomposition temperature, and in particular in non-oxidizing atmospheres, their complete decomposition is difficult to complete and remain as carbides. For example, when firing a ceramic molded body, When the carbides that could not be decomposed and removed remain in the molded body that is a sintered body, the desired performance cannot be exhibited and various problems occur. In order to completely decompose and remove these, a degreasing treatment or a high-temperature and long-time heat treatment is required. When production costs and production efficiency are taken into account, or when heat treatment at high temperatures is not possible and molding by low-temperature firing is required, a binder that easily decomposes and volatilizes or burns out at low temperatures is desired. .

  Specifically, in the case of a multi-layer ceramic conductor (MLCC), it has a structure in which dielectric layers and internal electrode layers are alternately laminated. In general, the former is a butyral resin as a binder for firing on barium titanate. However, in the latter, an ethyl cellulose resin is used as a baking binder for a conductor such as nickel. Moreover, said binder is used for conductors, such as aluminum and silver, also for the electrode of the silicon wafer for solar cells. In recent years, however, these binders have become insufficiently thermally decomposable in response to demands for downsizing, high performance, and workability, requiring long-time firing and sintering at high temperatures, and are not completely removed by firing. If it remains, the performance such as electrical characteristics will be degraded.

  An example of such a resin having low temperature decomposability is poly-α-methylstyrene. This poly-α-methylstyrene is completely decomposed and volatilized around 300 ° C., but has poor moldability and is expensive.

  As an improvement of this, Patent Document 1 discloses a thermally decomposable styrene copolymer obtained by copolymerizing styrene and α-methylstyrene. It has been reported that a copolymer obtained from 30 to 90 parts by weight of styrene and 10 to 70 parts by weight of α-methylstyrene is thermally decomposed at 385 ° C. under reduced pressure.

JP-A-6-41241

  The present invention has been made in order to solve the above-mentioned problems, and has excellent thermal decomposability that can be pyrolyzed at a low temperature or an extremely low temperature condition of 250 ° C. or less, and is fired corresponding to a wide range of firing temperatures. It is an object of the present invention to provide a binder for firing that can be used in production and contributes to production cost and production efficiency.

  As a result of intensive studies to solve the above problems, the present inventors have found that an ester having a tertiary alcohol ester group in which a tertiary alcohol having a molecular weight of 300 or less and a mono- and / or di-carboxylic acid are ester-bonded. The compound was found to thermally decompose at an extremely low temperature of 250 ° C. or lower, and the present invention was completed.

The binder for baking according to claim 1, which has been made to achieve the above object, is an alcohol compound having two tertiary alcohol hydroxyl groups in one molecule and a tertiary alcohol in one molecule. hydroxyl group and tertiary alcohols having a molecular weight of 300 at the maximum molecular weight is selected from an alcohol compound having one carboxyl group is also 300 at maximum mono - and / or di - tertiary alcohol and carboxylic acids plural ester-linked A polyester oligomer or a polyester resin , which is an ester compound containing a polyester skeleton having an ester group , is included.

The binder for firing according to claim 2 is the binder according to claim 1, wherein the ester compound has a repeating structure of polyester bonds of the plurality of tertiary alcohol ester groups , or characterized in that said a plurality of the polyester oligomer or the polyester resin is a polyester compound the tertiary alcohol ester groups and non-repetitive structure in two.

  The binder for firing according to claim 3 is the binder according to claim 1 or 2, wherein the ester compound has a total atomic weight of atoms constituting a plurality of the third alcohol ester groups. The maximum value is 300.

  The binder for baking of Claim 4 is described in any one of Claims 1-3, Comprising: The said ester compound is the 1st and / or 2nd alcohol and molecular weight of 300 at the maximum, and the said It is a polyester oligomer or polyester resin having primary and / or secondary alcohol ester groups in which mono- and / or di-carboxylic acids are ester-bonded.

The method for producing a binder for baking according to claim 5 is selected from an alcohol compound having two tertiary alcohol hydroxyl groups in one molecule and an alcohol compound having one tertiary alcohol hydroxyl group and one carboxyl group in one molecule. tertiary alcohols with molecular weight of 300 the molecular weight of at most 300 mono at most - and / or di - by esterifying a carboxylic acid, to form a plurality of tertiary alcohol ester group, an ester compound containing a polyester backbone It includes a step of synthesizing a certain polyester oligomer or polyester resin .

  The method for producing a binder for firing according to claim 6 is the method according to claim 5, wherein after the formation of the third alcohol ester group, the first and / or second molecular weight is 300 at the maximum. The method includes the step of esterifying by adding an alcohol to form a first and / or second alcohol ester group and synthesizing the ester compound.

  The binder composition for baking of Claim 7 contains the binder for baking and the inorganic powder in any one of Claims 1-4, It is characterized by the above-mentioned.

  The binder for firing according to the present invention can be easily decomposed and removed even at a very low temperature of 250 ° C. or less in a non-oxidizing gas atmosphere or an inert gas atmosphere. This binder for baking can be used corresponding to a wide range of baking temperatures as a binder for forming ceramics or forming electrodes. In addition, it is possible to sinter as fast as 50 to 100 ° C. compared with a readily heat-decomposable acrylic resin without the need for decomposition and removal by heat treatment for a long time at a high temperature as in the past. Contributes to improving productivity such as production efficiency and energy efficiency. Further, it can be decomposed in the first half of the 200 ° C. range, and can be used for surface processing of organic materials that are difficult to heat-treat at high temperatures such as plastic substrates such as polyamide resins.

  According to the method for producing a binder for firing of the present invention, an ester compound having a controlled molecular structure can be obtained, and a binder for firing that can be decomposed even by low-temperature firing can be provided.

  The binder composition for baking of this invention can form the sintered compact which sintered the inorganic powder contained by baking. This binder composition for baking can be used as a forming material for forming a wiring pattern used for a ceramic molded body, a solar cell, or the like, and molding an electrode or a dielectric.

  Hereinafter, although embodiment of this invention is described in detail, the scope of the present invention is not limited to these forms.

  The binder for baking of the present invention contains an ester compound having a tertiary alcohol ester group in which a tertiary alcohol having a molecular weight of 300 or less and a mono- and / or di-carboxylic acid having a molecular weight of 300 or less are ester-bonded. . Here, in the following chemical formula, a skeleton called a tertiary alcohol ester group is indicated by a dotted frame.

  The ester compound may be a low molecular compound having at least one tertiary alcohol ester group (—COO—) that is an ester bond derived from a tertiary alcohol, or may be a polyester oligomer or a polyester resin having a plurality thereof.

  In the case of having one tertiary alcohol ester group, each tertiary alcohol is composed of a tertiary alcohol ester group in which a tertiary alcohol having a molecular weight of 300 or less and a mono- and / or di-carboxylic acid are ester-bonded. The total atomic weight of the atoms constituting the trialcohol ester group to each terminal is 300 or less.

  When two or more tertiary alcohol ester groups are present, the total atomic weight of atoms constituting the tertiary alcohol ester group to each terminal is 300 or less, and between the third alcohol ester groups is formed as described above. The total atomic weight of the atoms to be reduced is 300 or less. Accordingly, the polyester such as a polyester oligomer or polyester resin having a plurality of tertiary alcohol ester groups has a total atomic weight of 300 or less between the respective tertiary alcohol ester groups. Here, between the third alcohol ester groups means between the third alcohol ester group (—COO—) and the adjacent third alcohol ester group (—COO—).

  The total atomic weight of 300 or less is the total of atoms between the adjacent atom and the atom adjacent to the terminal atom or the next tertiary alcohol ester group excluding the atomic weight of the tertiary alcohol ester group (—COO—). It is calculated as atomic weight.

  If the total amount of such atomic weights exceeds 300, thermal decomposition products at low temperatures remain without volatilization, and thus a temperature of 250 ° C. or higher is required for decomposition. If the total atomic weight is 300 or less, the molecular structure is not particularly limited as long as the thermal decomposition is not significantly adversely affected.

  The ester compound may have a primary and / or secondary alcohol ester group in which a primary and / or secondary alcohol having a molecular weight of 300 or less and the mono- and / or di-carboxylic acid are ester-bonded. Good. The first and / or second alcohol ester group has a range in which the total atomic weight of atoms constituting between the third alcohol ester groups does not exceed 300 between the third alcohol ester group and the third alcohol ester group. Can have one or more.

  Below, the manufacturing method of an ester compound is demonstrated in detail.

  The ester compound is obtained by esterifying a tertiary alcohol having a molecular weight of 300 or less and a mono- and / or di-carboxylic acid to form a tertiary alcohol ester group.

  Examples of tertiary alcohols include alcohol compounds having two tertiary alcohols in one molecule such as 2,5-dimethyl-2,5-hexanediol and 2,4-dimethyl-2,4-pentanediol; Examples include alcohol compounds having one tertiary alcohol and one carboxyl group in one molecule such as 2-methyl-2-hydroxypropionic acid and 3-methyl-3-hydroxybutanoic acid.

  Examples of mono-carboxylic acids include linear or branched carboxylic acids such as acetic acid, propionic acid, isopropionic acid, butanoic acid, lauric acid and stearyl acid, and unsaturated carboxylic acids such as acrylic acid and methacrylic acid. It is done. Examples of the dicarboxylic acids include dibasic acid chlorides such as succinic acid dichloride and citraconic acid dichloride; hexahydrophthalic anhydride, succinic anhydride, maleic anhydride, citraconic anhydride, maleic anhydride, and methyl-hexahydrophthalic anhydride. And acid anhydrides. Further examples include acid anhydrides having a plurality of anhydride rings such as pyromellitic dianhydride and biphenyltetracarboxylic dianhydride.

  Hereinafter, specific reaction examples will be described in detail.

  As shown in the following reaction formula (1), 2,5-dimethyl-2,5-hexanediol which is an alcohol compound (A) having two tertiary alcohols in one molecule and dibasic acid chloride (B) An ester compound can be obtained by dehydrohalogenating a succinic dichloride.

  In the reaction formula (1), n represents a repeating unit. The obtained ester compound is a polyester having a plurality of tertiary alcohol ester groups in which a tertiary alcohol is esterified. This polyester is a mixture of many kinds of oligomers or polymers mainly containing, for example, 6 to 10 mer, preferably 6 to 7 mer.

  In addition to the third alcohol ester group, the first and / or second alcohol having a molecular weight of 300 or less can be added to the obtained ester compound by further adding a diol compound such as a first and / or second alcohol. And ester compounds having primary and / or secondary alcohol ester groups in which the mono- and / or di-carboxylic acids are esterified.

  For example, 1 mol of an alcohol compound (A) having two tertiary alcohols in one molecule and 2 mol of a dibasic acid chloride (B) are reacted, and the diol compound (C) is further added and reacted. A polyester having a structure as shown in reaction formula (2) is obtained.

  In the above-described schematic reaction formula (2), the B-A and AB bond portions are each a third alcohol ester group, and the BC and CB bond portions are derived from the first and / or second alcohol, respectively. A first and / or second alcohol ester group which is an ester bond.

  The diol compound (C) is an alcohol having a molecular weight of 300 or less and having a primary alcohol and / or a secondary alcohol, and the total number of atoms constituting the space between the tertiary alcohol ester groups upon esterification. It may be in the range where the atomic weight does not exceed 300. Examples of the diol compound (C) include ethylene glycol and propylene glycol.

  The content of each compound in the reaction step is 30 to 100 parts by weight of the alcohol compound (A) and dibasic acid chloride (B) having two tertiary alcohols in one molecule, and the diol compound (C). Is 0 to 70 parts by weight.

  As another production method of the ester compound used in the present invention, as shown in the following reaction formula (3), 2,5-dimethyl-2,5-hexane which is an alcohol compound (A) having two tertiary alcohols An ester compound having two tertiary alcohol ester groups can be obtained by addition reaction of succinic anhydride, which is an acid anhydride (D), with the hydroxyl group of the diol. Alternatively, as shown in the following reaction formula (4), an acid is added to the hydroxyl group of 2-methyl-2-hydroxypropionic acid which is an alcohol compound (A ′) having one tertiary alcohol and one carboxyl group in one molecule. An ester compound having one tertiary alcohol ester group can be obtained by addition reaction of succinic anhydride which is an anhydride (D).

  These ester compounds may be ester bonds derived from primary and / or secondary alcohols by reacting with diol compounds such as primary and / or secondary alcohols as described above, if necessary. Polyesters having one and / or secondary alcohol ester groups can be obtained.

  As this reaction step, for example, a carboxyl group introduced from the acid anhydride (D) by reacting a large excess of the acid anhydride (D) with the alcohol compound (A) having two tertiary alcohols. Is obtained at both ends. A diol compound (C) is added to this and subjected to dehydration condensation, whereby a polyester having a structure as shown in the following schematic reaction formula (5) can be obtained.

  Similarly, the alcohol compound (A ′) having one tertiary alcohol and one carboxyl group is reacted with the acid anhydride (D), the carboxyl group introduced from the acid anhydride on one side, and the alcohol compound (A on the other side) An ester compound having an unreacted carboxyl group is obtained. A diol compound (C) is added to this and subjected to dehydration condensation, whereby a polyester having a structure as shown in the following schematic reaction formula (6) can be obtained.

  In the formula, the bonds of DA, AD, A′-D and DA ′ are tertiary alcohol ester groups, respectively, and are represented by DC, CD, CA ′ and A′—. The C bond is a first and / or second alcohol ester group, respectively.

  The polyester shown in the reaction step has a plurality of tertiary alcohol ester groups, and has a total atomic weight of 300 or less each constituting between the tertiary alcohol ester groups. As the acid anhydride (D), those exemplified above can be used similarly, and those having a molecular weight of 180 or less are preferable. As the diol compound (C), those exemplified above can be used similarly, and those having a molecular weight of 80 or less are preferable.

  The content of each compound in the reaction step is an alcohol compound (A) having two tertiary alcohols in one molecule or an alcohol compound (A ′) having one tertiary alcohol and one carboxyl group in one molecule. And the acid anhydride (D) is 30 to 100 parts by weight, and the diol compound (C) is 0 to 70 parts by weight.

  In addition, the ester compound used in the present invention utilizes a third esterification reaction obtained by Markovnikov addition of a carboxylic acid to a double bond, for example, an addition reaction between a diene compound and a dicarboxylic acid compound, Polyester obtained by addition reaction of a compound having a heavy bond and a carboxyl group may be used.

  Examples of the diene compound include 2,7-dimethyl-2,6-octadiene and 2,5-dimethyl-2,4-hexadiene.

  Examples of the dicarboxylic acid compound include succinic acid, phthalic acid, and hexahydrophthalic acid.

  Examples of the compound having a double bond and a carboxyl group in one molecule include 4-methyl-3-pentenoic acid.

  As a reaction step of the ester compound used in the present invention, any synthesis method may be used as long as it is a reaction capable of obtaining a tertiary alcohol ester group, and it is limited to the production method exemplified here. is not. In these reactions, a reaction catalyst and an aprotic solvent can be appropriately used.

  The weight average molecular weight of the ester compound used in the present invention is 500 or more, more preferably 1000 or more. Moreover, the ester compound may contain the thing of a different polymerization degree.

  The binder for sintering of the present invention containing these ester compounds shows a thermal decomposition product of 99% or more when the temperature reaches 250 ° C. under the condition of heating at a rate of temperature increase of 10 ° C./min in a nitrogen stream. Is. By heating the sintering binder, the tertiary alcohol ester group of the ester compound contained therein is cleaved, decomposed and removed. When the ester compound has a primary and / or secondary alcohol ester group, it is difficult to cleave between these ester bonds, but it can be removed by sublimation by heating because of its low molecular weight. is there.

  The binder for baking of this invention may contain other resin, various additives, a plasticizer, a diluent solvent, etc. other than the said ester compound as needed.

  Examples of other resins include polyol compounds such as polymers composed of acrylic acid esters and methacrylic acid esters, polyethers, polyesters, and polycarbonates. Examples of the additive include, but are not particularly limited to, plasticizers such as phthalate esters (or solvents having a relatively high boiling point (boiling point: 180 ° C. or higher)), such as paint / resin dispersants and thixotropic agents. Examples of the dilution solvent include solvents such as aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, ketone solvents, ether ester solvents, and ester solvents.

  Examples of the aliphatic hydrocarbon solvent include hexane, cyclohexane, isohexane, cyclohexane, methylcyclohexane, normal heptane, isooctane, and normal decane.

  Examples of the aromatic hydrocarbon solvent include toluene and xylene.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, DIBK (diisobutyl ketone), and cyclohexanone.

  Examples of the ether ester solvent include methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3 -Ethyl ethoxypropionate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, 2-methoxy-2-methylpropionic acid Methyl, ethyl 2-ethoxy-2-methylpropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl Ether acetate, propylene glycol monopropyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, and the like diethylene glycol monobutyl ether acetate.

  Examples of the ester solvent include ethyl acetate, methyl acetate, butyl acetate, methoxybutyl acetate, cellosolve acetate, amyl acetate, normal propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, and butyl lactate.

  The binder for baking becomes a binder composition for baking by mixing or kneading with inorganic powder.

  The binder composition for firing of the present invention is formed by sintering and sintering the contained inorganic powder while being decomposed and removed by firing.

Examples of the inorganic powder include inorganic fillers such as TiO ₂ , BaTiO ₃ , MgTiO ₃ , CaTiO ₃ , and SrTiO ₃ , metal particles such as Ni, Cu, Ag, and Al, and ceramic particles.

  Although content of the binder for baking and inorganic powder in a binder composition for baking is not specifically limited, The addition amount of the binder for baking is 5% or more with respect to inorganic powder, Preferably it is preferable in it being 10% or more. Examples of these mixing methods include a method of uniformly mixing and defoaming with a ball mill or the like.

  The binder composition for baking of the present invention may be one in which various additives are mixed as necessary. Examples of the various additives include a plasticizer, a dispersant, a thickener, an antifoaming agent, and a leveling agent. These additives are required to have thermal decomposability depending on the application. Examples of the plasticizer include phthalic acid esters such as dioctyl phthalate and diisopropyl phthalate. Examples of the dispersant include acrylic acid-acrylic acid ester copolymer ammonium salt, polyacrylic acid ammonium salt, modified polymer containing carboxyl group, and the like. Examples of the thickener include polyacrylic acid.

  Hereinafter, the example which synthesize | combined the binder for baking which applies this invention and used it for the binder composition for baking is shown as an example.

Example 1
A polyesterification reaction of 2,5-dimethyl-2,5-hexanediol and succinic dichloride by dehydrochlorination was performed as follows. First, 2,5-dimethyl-2,5-hexanediol (1.00 g / 6.84 mmol) and dehydrated THF (13.7 ml) were added to a 50 ml flask and stirred under a nitrogen atmosphere. To this, a 2.6 M / L hexane solution (5.2 ml / 13.7 mmol) of n-butyllithium was added dropwise over 10 minutes using a dropping funnel while controlling the liquid temperature at 0 ° C. After aging for 5 minutes, succinic dichloride (750 μl / 6.84 mmol) was added dropwise over 10 minutes and further aging at room temperature for 2 days. After the reaction mixture was concentrated and filtered, ethyl acetate was added, and the mixture was washed once with a saturated aqueous sodium bicarbonate solution and a saturated aqueous sodium chloride solution, and then the solution was removed under reduced pressure. The obtained crude product was dissolved in THF and then added dropwise to water to obtain a polyester (168 mg).

  The weight average molecular weight of the obtained polyester was gel permeation chromatography (GPC) (solvent: tetrahydrofuran (THF), column: Shodex KF-G, KF-802 × 4, KF-800D (manufactured by Showa Denko KK), flow rate. 1 mL / min, temperature: 40 ° C.) and 3,000 when converted to styrene.

(Example 2)
An esterification reaction between 1 mol of 2,5-dimethyl-2,5-hexanediol and 4 mol of Ricacid MH-700 (a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride) was performed as follows. First, Rikacid MH-700 (mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride) (23.0 g / 140 mmol), 2,5-dimethyl-2,5-hexanediol (5.00 g) was added to a 50 ml flask. /34.2 mmol), Kaolinizer No. 20 (5 drops) and toluene (5 g) were added, and the mixture was stirred at 90 ° C. for 24 hours under a nitrogen atmosphere. Toluene (30 g) was added to the reaction mixture, and recrystallization gave an ester compound (a) represented by the following chemical formula (4.90 g / yield 29.7%).

(Comparative Example 1)
Esterification reaction of 1 mol of ethylene glycol and 2 mol of Ricacid MH-700 was performed as follows. In a 100 ml flask, Ricacid MH-700 (55.5 g / 339 mmol), ethylene glycol (10.0 g / 161 mmol), Kaolinizer No. 20 (1.09 g / 8.06 mmol) was added, and the mixture was stirred at 100 ° C. for 6 hours under a nitrogen atmosphere. The obtained reaction mixture was subjected to high performance liquid chromatography (HPLC) (solvent: tetrahydrofuran (THF), column: Shodex KF-G, KF-802 × 4, KF-800D (manufactured by Showa Denko KK), flow rate: 1 mL / min. , Temperature: 40 ° C.), a third ester bond-free ester compound (b) (63.9 g) represented by the following chemical formula was obtained with a purity of 94%.

Example 3
The polyesterification reaction of the ester compound (a) and ethylene glycol was performed as follows.
Ethylene glycol (261 mg, 4.22 mmol), ester compound (a) (2.00 g, 4.22 mmol) and TA-10 (one drop) were added, and the reaction temperature was increased from 170 ° C. by 10 ° C. every hour. The mixture was stirred for 7 hours at a temperature of GPC (solvent: tetrahydrofuran (THF), column: Shodex KF-G, KF-802 × 4, KF-800D (manufactured by Showa Denko KK), flow rate: 1 mL / min, temperature: 40 ° C.) and converted to styrene to obtain 3,150 polyester (2.06 g).

Example 4
An esterification reaction between 1 mol of 2,5-dimethyl-2,5-hexanediol and 2 mol of succinic anhydride was performed as follows.
In a 100 ml flask equipped with a reflux tube, succinic anhydride (6.84 g / 68.4 mmol), 2,5-dimethyl-2,5-hexanediol (5.00 g / 34.2 mmol), DMAP (418 mg / 3. 42 mmol), triethylamine (14.4 mL / 102 mmol) and toluene (60 mL) were added, and the mixture was stirred at 110 ° C. for 2 hours under a nitrogen atmosphere. Then, succinic anhydride (6.84 g / 68.4 mmol) was added every 2 hours. The mixture was added and stirred for 17 hours. The obtained reaction mixture was diluted with toluene, and the supernatant was recovered, washed once with a saturated aqueous sodium chloride solution, and then the solution was removed under reduced pressure. Ethyl acetate was added to the obtained crude product, and recrystallization gave an ester compound (c) represented by the following chemical formula (3.03 g / yield 25.8%).

(Reference Example 1)
Esterification reaction of 1 mol of ethylene glycol and 2 mol of citraconic anhydride was performed as follows. First, in a 20 ml sample tube, citraconic anhydride (3.80 g / 33.9 mmol), ethylene glycol (1.00 g / 16.1 mmol), kaolinizer no. 20 (65.0 mg / 0.480 mmol) was added, and the mixture was stirred at 70 ° C. for 7 hours under a nitrogen atmosphere, and then stirred at 100 ° C. for 9 hours. The obtained reaction mixture solution was obtained by high performance liquid chromatography to obtain an ester compound (d) (4.86 g) represented by the following chemical formula with a purity of 53.1%.

(Comparative Example 2)
The polyesterification reaction between ethylene glycol and citraconic anhydride was carried out as follows. Add citraconic anhydride (5.40 g / 48.4 mmol), ethylene glycol (3.00 g / 48.4 mmol), TA-10 (one drop) to a 20 ml sample tube, and stir at 150 ° C. for 11 hours in a nitrogen atmosphere. Then, ethylene glycol (1.00 g / 16.1 mmol) was further added and stirred for 13 hours. Finally, the mixture was stirred at 180 ° C. for 9 hours, so that the weight average molecular weight was changed to GPC (solvent: tetrahydrofuran (THF), column: Shodex KF). -G, KF-802 × 4, KF-800D (manufactured by Showa Denko KK), flow rate: 1 mL / min, temperature: 40 ° C.) and converted to styrene, 5,000 polyester (7.46 g) was obtained. Obtained.

(Evaluation of the physical properties)
The thermal decomposability was measured using a thermal analyzer TG-8120 (manufactured by Rigaku Corporation) and increasing the temperature from room temperature to 500 ° C. at 10 ° C./min under 50 mL / min nitrogen using alumina as a standard substance. Table 1 shows the results of decomposition at 250 ° C. or lower as ◯ and those that did not decompose as ×.

  In Table 1, among the obtained ester compounds, a polyester having a plurality of ester bond repeating structures is referred to as a polymer compound, and a compound having one or two ester bonds and a non-repeating structure is referred to as a low molecular compound. The total atomic weight between the bonds indicates the total atomic weight of atoms constituting between the tertiary alcohol ester groups. Moreover, when the obtained ester compound is a low molecular compound, it shows as a molecular weight, and when it is a high molecular compound, it shows as a weight average molecular weight.

From Table 1, Examples 1, 2, and 4, which are ester compounds used for the binder for firing of the present invention, each have a tertiary alcohol ester group, and atoms constituting the tertiary alcohol ester groups. It was revealed that the total atomic weight of the carbon dioxide did not exceed 300 and decomposed at an extremely low temperature of 250 ° C. or lower.
Since Comparative Example 1 did not contain a tertiary alcohol ester group and the molecular weight of the obtained polyester compound exceeded 300, it was revealed that it remained without being decomposed.
Reference Example 1 was an ester compound of an alcohol compound having a primary alcohol with a molecular weight of 300 or less and an acid anhydride, and was a low molecular weight compound, so it was revealed that it did not remain.
Comparative Example 2 was a polyester composed of ester bonds derived from primary alcohols, and it was revealed that these polyester bonds were not decomposed and remained high because they were polymer compounds.

  The binder for firing of the present invention is useful as a binder for molding ceramics and electrodes for low-temperature firing type, and is a surface treatment material for organic materials that are difficult to process at high temperatures such as plastic substrates such as polyimide resins. As a general purpose.

Claims (7)

It is selected from an alcohol compound having two tertiary alcohol hydroxyl groups in one molecule and an alcohol compound having one tertiary alcohol hydroxyl group and one carboxyl group in one molecule, and has a maximum molecular weight of 300 tertiary alcohols with a maximum molecular weight. But 300 mono - and / or di - firing binder and the carboxylic acid is characterized in that the polyester oligomer or a polyester resin an ester compound containing a polyester skeleton, including having a plurality of tertiary alcohol ester groups by ester bonds . The polyester wherein the ester compound, a polyester polymer compound having a repeating structure of polyester binding of said plurality of tertiary alcohol ester group, or a plurality of tertiary alcohol ester groups is a polyester compound to non-repetitive structure in two It is an oligomer or the said polyester resin, The binder for baking of Claim 1 characterized by the above-mentioned.   The binder for firing according to claim 1 or 2, wherein the ester compound has a total atomic weight of atoms constituting between the plurality of tertiary alcohol ester groups of 300 at the maximum.   A polyester oligomer having a first and / or second alcohol ester group in which the ester compound is ester-bonded with a first and / or second alcohol having a molecular weight of 300 at the maximum and the mono- and / or di-carboxylic acid. Or it is a polyester resin, The binder for baking in any one of Claims 1-3 characterized by the above-mentioned. It is selected from an alcohol compound having two tertiary alcohol hydroxyl groups in one molecule and an alcohol compound having one tertiary alcohol hydroxyl group and one carboxyl group in one molecule, and has a maximum molecular weight of 300 tertiary alcohols with a maximum molecular weight. However, the method includes esterifying 300 mono- and / or di-carboxylic acids to form a plurality of tertiary alcohol ester groups and synthesizing a polyester oligomer or polyester resin which is an ester compound containing a polyester skeleton. The manufacturing method of the binder for baking characterized by these.   After the formation of the third alcohol ester group, the first and / or second alcohols having a molecular weight of at most 300 are added and esterified to form the first and / or second alcohol ester groups, and the ester compound The method for producing a binder for firing according to claim 5, further comprising a step of synthesizing.   A baking binder composition comprising the baking binder according to any one of claims 1 to 4 and an inorganic powder.